Approaches for making bubble-domain materials

Abstract

The garnet materials system has provided the basis for a rapid fundamental transformation of cylindrical magnetic bubble-domain materials technology from one based on bulk single crystals to one based on epitaxy. Recent developments are reviewed in an effort to provide some perspective on the nature of this transformation and its promise for exploitation. The intrinsic adaptability of the garnet system has permitted high degrees of substrate-epitaxial film lattice matching along with structural and chemical compatibility. As a result, it has been possible to grow liquid-phase hetero-epitaxial films with the ease and simplicity usually associated with homoepitaxy, while yet retaining the flexibilities of heteroepitaxial systems. These films thus exhibit only a few defects per square centimeter and have been used with 10 000-step shift registers. The rare-earth gallium garnet substrate growth capabilities are also described as well as chemical-vapor deposition epitaxial technology and its comparison with liquid-phase epitaxy.